<template>
  <div class="qrcode">
    <div id="reader"></div>
  </div>
</template>

<script>
import { Html5Qrcode } from 'html5-qrcode'
export default {
  created() {
    this.getCameras()
  },
  beforeDestroy() {
    this.stop()
  },
  methods: {
    getCameras() {
      Html5Qrcode.getCameras()
        .then((devices) => {
          if (devices && devices.length) {
            this.html5QrCode = new Html5Qrcode('reader')
            this.start()
          }
        })
        .catch((err) => {
          // handle err
          this.html5QrCode = new Html5Qrcode('reader')
          this.error = 'ERROR: 您需要授予相机访问权限'
          this.$emit('err', this.error)
        })
    },
    start() {
      //environment后置 user前置
      this.html5QrCode
        .start(
          { facingMode: 'environment' },
          {
            fps: 2,
            qrbox: { width: 250, height: 250 },
          },
          (decodedText, decodedResult) => {
            this.$emit('ok', decodedText)
          },
        )
        .catch((err) => {
          this.$emit('err', err)
        })
    },
    stop() {
      this.html5QrCode
        .stop()
        .then((ignore) => {
          // QR Code scanning is stopped.
          console.log('QR Code scanning stopped.')
        })
        .catch((err) => {
          // Stop failed, handle it.
          console.log('Unable to stop scanning.')
        })
    },
  },
}
</script>

<style lang="less" scoped>
.qrcode {
  margin-top: 20vh;
  height: 100vh;
  width: 100%;
  background: rgba(0, 0, 0, 0.5);
}

#reader {
  top: 50%;
  left: 0;
  transform: translateY(-50%);
}
</style>
